1.) Placing blame creates defensiveness.
Too often when things are being negotiated-- whether in marriages, friendships, or businesses--people tend to get frustrated, anxious, and defensive. Once defenses go up, people want to give up on working towards a solution. Solutions can be tough enough to arrive at when people are all working together, and they are much less likely to be found when there are defensive walls up among the parties.
2.) Placing blame creates uneasiness.
This is especially true in the mergers and acquisitions world. When deals are being negotiated and closings are imminent, senses are heightened and anxieties are in full bloom. There are always twists, turns, tweaks, and adjustments that have to be made. The greater number of moving parts, the greater the chance that adjustments will be necessary. When we blame others for things that go wrong during these adjustment periods, the uneasiness we feel can interfere with our ability to think clearly.
3.) Placing blame creates questions.
In an intense negotiation or discussion, the natural human reaction is to begin to question the other party and get frustrated with them. In that moment, someone has to keep a level head and not accuse or blame the other even if it's obvious who is at fault. Otherwise, people will naturally become untrusting and the negotiation can stall.
After the situation is settled, we must inquire and explore how things might have gone better. Learn from the past, try not to repeat the mistakes, and don't create additional hurdles of dissension in the present.
Deal making is an art, and the goal is ultimate resolution.